Tuesday 26 April 2016

wall thickness and acoustic impedance


I want to know how the geometry,more specificaly a thickness of simple wall affects how much will sound be reflected and how much will pass through.


I tried to search this on google for one and half hours but I didnt found single article or even single graph dedicated to this topic.I got bunch of thickness vs absorbtion stuff but that is not of interest for me,absorbtion and reflection are different things,perfect absorber have zero reflection.


Every article I found only talker about acoustic impedance of solid material compared to air,but it never mentions the thickness of the solid material.My point is,tungsten have 230000 times bigger impedance than air,but if you make wall of tungsten that is very thin,like lets say 100 atoms thick,then it will reflect sound less than if the wall was 1 meter thick.


If I know the impedance of air,if I know the intrinsic impedance of the material,then how do I calculate how much is reflected and how much transmitted at specific freqency and specific wall thickness?


Can you please give me links to articles or studies/white papers that are about wall thickness impact on reflectance? What words should I type in google so it give me results that are about reflectance/transmittance vs wall thickness instead of articles that talk purely about either absorbtion vs wall thickness or just mention that materials with increasing impedance difference cause increasing sound reflection but never mentions the critical aspect,the key factor that this all depends on the thickness of that wall not just intrinsic acoustic impedance of the material its made from.




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